And I'm Audie Cornish. The new film "Killer Joe" opened in theaters in limited release last month. It stars Matthew McConaughey, who's been garnering critical acclaim for his role as Joe Cooper.

(SOUNDBITE OF MOVIE, "KILLER JOE")

EMILE HIRSCH: (as Chris Smith) Do you ever hear of Joe Cooper? He's a cop, a detective, actually. Got a little business on the side.

THOMAS HADEN CHURCH: (as Ansel Smith) What's he do?

HIRSCH: (as Chris Smith) He kills people.

CORNISH: Oh, and he's sadistic, and there are some graphic violent and sexual content. So the movie won an NC-17 rating. That means no one 17 or under will be admitted into a theater showing "Killer Joe," and it means some theater chains won't even play the film. Some newspapers won't carry ads for it, and some retailers won't sell it on DVD. As my next guest recently wrote in the Los Angeles Times, the Motion Picture Association of America had different hopes for the NC-17 rating when it created it more than 20 years ago. Steven Zeitchik covers the film industry for the L.A. Times. Welcome, Steven.

STEVEN ZEITCHIK: Good to be here.

CORNISH: So explain how the NC-17 rating came about because it was a shift, right, from the old X rating.

ZEITCHIK: Exactly right. And it was a very big shift, and one that came with some pretty high expectations. Back in the late 1980s, Jack Valenti, who, of course, ran the Motion Picture Association for many years, realized that the X was getting completely exploited and kind of dragged through the mud as a lot of pornographic films, very kind of low-rent exploitation films were using the rating because it wasn't trademarked. So he and his team came up with this NC-17 rating, and the idea was basically to bring a little bit of sophistication, a little bit of credibility, really, to films with adult content. And, you know, sure enough, that is what happened at the beginning, in 1990, when it was created, but things quickly went south from there.

CORNISH: So, Steve, what kind of movie gets an NC-17 rating? I don't know if it's about violence or sex or both.

(LAUGHTER)

ZEITCHIK: Well, that's the $64,000 question. Nobody really knows. I mean, the only sort of published or explicit kind of rule about what gets you any rating is a certain number of obscenities that will get you an R rating from a PG-13. But outside of that, it's a very amorphous system. And certainly, when it comes to the NC-17, I mean, we've seen movies that seemed to have identical scenes in them. One of them last year or two years ago comes to mind. The movie "Blue Valentine" had an oral sex scene much like the movie "Black Swan" that came out about the same time.

It had an NC-17 rating. Very similar scenes, very similar in duration, no nudity in either. One film was initially given the NC-17 - that was "Blue Valentine" - the other, "Black Swan," got an R. So no one can really make heads or tails of what exactly will tip the scales and get you that NC-17.

CORNISH: When the NC-17 rating first came about, were there any films that were successful under that rating?

ZEITCHIK: There were, and that what was sort of interesting about it is in the very early years of this rating, you had movies like "Henry & June" or "The Cook, the Thief, the Wife & Her Lover." These were kind of serious art house films, they had adult themes, they had sexual situations in them, but they were art house hits. You know, many people came out to see them. One of them, I think, grossed about 20-something million dollars in the box office in today's dollars. And, you know, people thought this was going to be a respectable rating just the way the R is, just with a little bit more adult content.

CORNISH: Now, how is it that the NC-17 rating hasn't turned out as planned? I mean, what is it about the films that have come out since that have undermined it in some way?

ZEITCHIK: Well, you know, what's interesting is that kind of as the '90s progressed, you started to see studios and distributors get more and more gun-shy about what films they were willing to release with the NC-17 rating. And I think the reason for that is because you started to see a resistance on the part, as you were saying, of theater chains and media outlets not to either carry or show the film or carry advertising for it. And I think what ended up happening was this sort of chicken-and-egg kind of effect where the filmmakers got a little more gun-shy.

The, you know, the retail outlets and then the media outlets started getting a little bit more cautious about what they're willing to show. The distributors and filmmakers got even more reluctant to get an NC-17. So if there was any danger that they were going to get branded with that rating, they would cut scenes from the film. And so now, we're at the point in 2012 where most films don't even come out with it, with an NC-17 rating. They either get cut to an R or, in some cases, it'd come out unrated and basically circumvent the rating system entirely. So we have a system now where the NC-17 is so stigmatized that most films don't even use it at all.

CORNISH: It was interesting in your article you also wrote that it was in some ways undermined by movies that weren't so good. One example you gave, for instance, was "Showgirls." I think we have a clip of that.

(SOUNDBITE OF MOVIE, "SHOWGIRLS")

ALAN RACHINS: (as Tony Moss) One day, she looks like Pollyanna. The next day, she looks like - I don't know - Lolita, maybe.

(Giggling)

(as Tony Moss) Nice dress.

ELIZABETH BERKLEY: (as Nomi Malone) Thanks. I bought it at Versayce.

RACHINS: (as Tony Moss) Oh, yeah, Versayce. I love Versayce.

ELIZABETH BERKLEY: (as Nomi Malone) Me too.

CORNISH: Versayce, instead of Versace, one of the many cringe-inducing scenes in "Showgirls." And you say that, you know, movies that came out under this rating sometimes were just bad.

ZEITCHIK: Well, the thing about "Showgirls" that's interesting, what's sort of funny about it is that Paul Verhoeven, who directed the movie, actively wanted the NC-17. I mean, he's one of the few directors, I think, and it was also an early point in the evolution of this rating, but he really sought it out, which is something no director now would do. And in fact, there was a moment as the film was being released where Verhoeven was afraid he wasn't going to get it and, in fact, was going to back to the cutting room floor, put back in additional sex scenes that he had cut out to ensure that he got it. But what it did, as you correctly point out, is it reinforced the perception that it's not a serious rating.

CORNISH: How serious is the debate about fixing this? What are the suggestions to improve this adult themed rating system?

(LAUGHTER)

ZEITCHIK: Well, it's a good question, and I don't think the efforts, unfortunately, are all that serious. You know, the thing about ratings, that they are a little bit like the weather. You know, everybody talks about them, but nobody does anything about it. And I think that's sort of where we are with this. I mean, you're starting to see a little bit more of a critical mass of both distributors and executives on the one hand and filmmakers on the other say, hey, look, we want to create serious adult content and not have it feel like it's going to be labeled porn.

You know, I think there's a little bit of a human cry from that camp, but it takes a lot to move the needle when it comes to the MPAA ratings. And at the moment, I don't think it's being moved very far.

(SOUNDBITE OF MUSIC)

CORNISH: That's Steve Zeitchik. He writes about the movie industry for the L.A. Times. He was talking about the current state of the NC-17 rating. Transcript provided by NPR, Copyright NPR.